Johnny Ball's climate science

• 24 Feb 2011, 18:11
• The Carbon Brief

Retired children's presenter Johnny Ball expressed fears this week that his school appearances have been cancelled and he is a victim of an internet smear campaign because of his climate scepticism. The news story has allowed Ball to outline his many doubts about climate science.

The allegations were first made in the Times Education Supplement which also suggested environmentalists launched a "malicious campaign" to sabotage Ball's work. The claims were picked up by the Times, the Daily Mail, the Telegraph and the Express.

However, Ball blogged on Tuesday denying he used the words "climate zealouts" or "global warming fascists" while the Guardian challenged the evidence that environmentalists were involved.

Ball was a fantastic television personality who presented science in a clear and concise way to millions of children. We're sure he won't mind if we now examine his scientific views, as expressed in a Daily Mail article on Tuesday, as clearly and concisely as we can.

Claim One:

"Along with water and oxygen, carbon dioxide is one of the three basic requirements for sustainable life. And yet this natural gas - only 4 per cent of which is produced by man - has been branded as the greatest threat to the future of this planet. Well, forgive me, but I think that's nonsense."

Man's output of 29 gigatons of carbon dioxide a year from burning fossil fuels is about four percent of the amount of carbon moving through the cycle each year. However, the carbon dioxide that man is adding is additional to the natural flow.

Carbon is absorbed and released by the oceans and vegetation each year (see graphic). But only a limited amount of carbon can be absorbed at any one time. Therefore only 40 percent of the human produced carbon goes into the earth and seas - the rest adds to what is in the atmosphere. As a result atmospheric carbon dioxide is currently at its highest level in 15 to 20 million years (Tripati 2009).

The fact that carbon dioxide causes warming of the atmosphere can be demonstrated in the laboratory. Many different experiments have confirmed this, as have observations of current temperature trends.

Claim Two:

 

"My own view, for what it's worth, is that the water content of air has far more impact on temperature than carbon dioxide levels do…Any increase in air temperature produced by raised water vapour levels will be minor and largely self-regulating…"

Water vapour is the dominant greenhouse gas. However its residence in the atmosphere is very short-lived compared to carbon dioxide. Therefore increasing atmospheric carbon dioxide has longer-lasting effects than increasing atmospheric water vapour.

Any water vapour present in the atmosphere enhances the warming effect of carbon dioxide by its short-lived greenhouse effect. This is because warming increases the evaporation rate of water, which increases the greenhouse effect, which increases warming. Therefore water vapour exacerbates the greenhouse effect, but carbon dioxide is the principal driver.

It has been suggested that increasing atmospheric water vapour will produce more cloud cover, which will reflect incoming sunlight and prevent further warming of the atmosphere. However, cloud cover also reflects the heat present in the atmosphere back towards the earth.

Satellites have observed an increase in atmospheric water vapour of about 0.41 kg/m² per decade since 1988. At the same time temperatures are also rising. In fact, between six and 7.5 percent of the warming we are experiencing in the lower atmosphere is attributed to this. (Santer 2007).

Claim Three :

"…Climate change is absolutely normal and in my lifetime has never yet resulted in any signs that should cause alarm…"

Whilst it is true that earth's climate has changed throughout it history, the warming trend observed over the last century cannot be explained except by man-made influence. Scientists have not yet found a natural cause for the warming, and they have studied many possibilities. The temperature rise of 0.7 degrees above pre-industrial levels has caused limited problems to industrialised society so far. But this says little about what a temperature rise of 3-4 degrees would be like.

Claim Four

"Scientists… realised that a 0.7C rise in global temperatures over the past 100 years was hardly the stuff of environmental Armageddon, so they looked for a particularly chilly year against which to compare today's figures, and found 1961. Suddenly, global temperatures had gone up at 0.7 degrees in just 50 years: now, that was more like it."

Some scientists may have chosen 1961 because that is precisely 50 years ago, but it is not really clear where this claim comes from.

The three main datasets agree that temperatures have been rising since the 1880s. They show that the steepest warming phase has taken place over the last three decades. And we know the 'noughties' were the hottest decade on record.

There has been roughly 0.75^oC warming since the beginning of the 20th Century. The Met Office in the UK and NASA and the NCDC in the US all made announcements to this effect in early 2011.

Ball has the best intentions and is motivated by his love of children. He writes passionately on his blog:

"My declared position on Climate Change is well known. It is born of my wanting to protect the next generation from alarmism, which is scaring children and putting many of them off the thought of scientific careers or confidence in the future or in trusting adults, politics or technology.

It does not seem logical to me, to tell kids that the older generation has screwed up the world so much, that we are in danger of the world not being able to support human life by 2050 - especially when it is patently not true."

Science often presents us with difficult facts. Some may argue that we as caring adults must confront the science in order to best protect our children from an uncertain future. Only then will we have earned their trust.